A chelating resin adsorbent containing an amidoxime group of capillary fiber form (AO-C fiber) was prepared by a radiation-induced grafting method. The reaction condition in amidoximation, for an optimized conversion of cyano group into an amidoxime group, was examined to obtain an adsorbent having an amount of amidoxime group,
i.e. 5.6 mol/kg of base polymer. The seawater was continuously pumped upwards through a novel fixed-bed, 30 cm in length and charged with a bundle of AO-C fibers. The adsorption rate and pressure drop were determined as a function of superficial velocity of seawater
u. For a superficial velocity of 36 m/h, the adsorption column was found to adsorb U from natural seawater at a high rate,
i.e. 0.27 g-U/kg of adsorbent of HCl type in 25 days. The cross-sectional area of the adsorption bed
S required to produce 10kg of U/yr using our AO-C fiber adsorbent was calculated to be
S (m
2)=404
u-0.50.
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